Liquid pump



June 16, 1942.

B. G. PARSONS LIQUID PUMP 2 *Sheets-Sheet l Filed Feb. 28, 1941.

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LLQUID` RUM? Filled Feb. 28, 1941 2 shets-sheet 2 INVENTOR.

APatented June 16, 1942 UNETED STATES PATENT AOFF-ICI?.4

LIQUID PUMP Ben G. Parsons, Detroit, Mich., assigner to American Bosch Corporation, Springfield, Mass., a corporation of New York Application February 28, 1941, Serial No. 381,067

20 Claims. (Cl. 10S-162) i The present invention relates to liquid pumps, and particularly to single cylinder and multicylinder pumps for supplying gasolene, fuel oil, water and other liquids to a nozzle or spray device in an amount which is metered and preferably begins at such a variable time in the engine cycle as is predetermined in accordance with an adjustable setting of the pump.

The primary object of the invention is to provide an arrangement whereby' there is obtained a small, strong, compact and inexpensive pump of this kind of comparatively large capacity with comparatively low working pressures, and light in weight but rigid in construction. `One of the preferred features contributing to these characteristics is a hollow delivery plungerA and a hollow control piston therefor in which are partly or wholly enclosed the return springs. Another preferred contributing feature has to do with multicylinder pumps with or without control pistons but with delivery ducts in the form of rigid tubes circularly spaced around the pump and substantially strengthening the structure thereof. I

Still another object is to provide in this or other kind of pump an improved stationary filter arrangement for the liquid supplied to the cylinder or cylinders thereof,-preferably' of the kind in which the outer periphery thereof is continually washed by the ow of liquid forming the surplus not discharged by the pump at the time and in which the cleansing of the filter is assisted by surplus liquid returned from the cylinder or cylinders through the filter.

The structural features and arrangements by which these and other objects are attained will be understood from the following description taken in connection with theI accompanying drawings, which show as examples single and multicylinder pumps particularly adapted in accordance with the invention for injecting gasolene through a nozzle or nozzles into the manifold or cylinders of internal combustion engines.

In the drawings, Fig. l is a central vertical section, partly in elevation and partly'diagrammatic, of a 9-cylinder pump with a manual adjustment for the beginning of injection and thequantity of delivery, in combination with ay nozzle`mounted in the engine manifold; Fig. 2 is a section of the pump on line 2-2 of Fig. 1; Fig. 3 shows in central section. partly in elevation, a modified form of manual adjustment; Fig. 4 is a central vertical section, partly in elevation, of a-single cylinder pump "shown with the delivery plunger in its .lowermost position; Fig.

is a sectionMpartly in elevation, on line 5-5 of Fig. 4 but with 'the plunger in its uppermost position; and Fig. 6 is a fragmentary view in vertical section of a modified form -of spring arrangement applicable to the multicylinder pump of Fig. 1 or the single cylinder pump of Fig. 4.

Referring to Figs. 1 and 2, the exterior casing is formed by a iilter housing I comprising an upper or cap portion 2 and an integral depending annular portion 3 of suitable aluminum alloy, and also by an integral plunger housing or v pump body 4 comprising a steel forging with a anged base 5 and an upstanding annular portion 6. These two housings, having their annular portions 3 and B-telescoped. are separated above by a copper ring 1 and below by a synthetic rubber ring 8. 9, bearing on the cap portion 2 and threaded into the pump body, hold the two' telescoped portions rigidly against rings l and 8. The lter housing contains a gasolene inlet I0 and outlet Il into which suitable conduits A(not shown) are screwed. The base 5 isI secured to the engine or other support I2 by a circular series of pickel steel or stainless steel stud bolts I3 comprising one for each pump cylinder.

Arranged concentricallywithin the filter rhousing. is a stationary filter comprising an annular l cage I4 of stainless steel, also secured between the rings I and 8, and an annular filter screen I5, of any suitable kind such as closely spaced bronze wires soldered to the cage at its upper and lower ends. The cage has a plurality of circularly arranged axial slots IB- staggered in its upper and lower halves. The pump body has nine circularly arranged delivery cylinders or barrels I1 around all oi which are two annular channels I 8 and I9 open respectively to the upper and lower slots I6. For the delivery barrels there is-a common inlet port 20 of ring form, and for each barrel there is adelivery or discharge port 2I and a leakage outlet or trap 22 of ring form. I

Also extending concentrically around the pum body within the channels` I8 and I9 is a plurality of nickel steel tubes 23,.with\plugs 24 in their ends as shown, each tube being arranged radially outside a delivery barrel and having its borev connected tothe delivery, port 2| thereof.

The tubes extend through the flanges 25 of the pump body,4 andbecause of the material and ar- I A,rangement there results a pump which is of great strength for its' weight, and rigid in con- The circular series of screws particularly on airplanes. The bore of each tube 23 extends into communicationwith a duct 26 which leads to. a circular recess 21 around a respective stud bolt |3 so that the tube communicates with the recess at any position to which the bolt; may be turned. From opposite points of ihisrecess extends the cross passage 28 'leading to the central bore 29 of the stud bolt, from which extends a pipe 30 to the respective nozzle 3| inthe manifold 32 of the engine. Air enters the manifold at 33, and, after mixing with "the gasolene spray emerging from the nozzle, enters the engine cylinder through the inlet valve 34.

In each barrel |1 is a hollow delivery plunger 35 of chromesteel having a rounded bottom 36. Above each delivery plunger is a chrome steel control piston 3.1 with open ends and cross web 38. A long helical spring 39 extends from the bottom of the delivery plunger to the web of the control piston, and a shorter but stiffer helical spring 40 extends from. the web 38 into a pocket 4| in the underside ofan adjustable stop plate 42. Centrallyv of the pump body near the bottom of the central bore therein is a drive shaft 43 mounted on ball bearings 44 and 45 and having a serrated end 46 for an adjustable erated from the power shaft 62 through eccentric 63 fast thereon, between the lowermos't and uppermost positions as shown. The ring 64 is supported by the eccentric on a needle bearing 65 and rises and falls without turning as a result of the downward pressure exerted on it by the delivery plunger 66. Above this plunger isthe control piston 61, these and the springsl68 and drive coupling (not shown) with or without an automatic timing device as desired. This shaft carries eccentrically an inner ball race 41 of which the outer ball race 48 carries a iiat topped swash plate 49 so that as the shaft rotates, the swash plate is given a circularly-advancing tilting movement without rotation and thereby lifts the delivery plungers serially'in movements of sine wave characteristic. In this way there is a rolling action between the swash plate and the rounded bottom 36 of each delivery plunger with substantially no sliding friction between them. The delivery plungers 35 are thus given upward movements progressively around the circle and with them the respective control pistons 31 are moved correspondingly upwardly until they in turn contact the stop plate 42. After each control piston is stopped, as shownv at the right in Fig. l, the corresponding delivery plunger alone continues its lift and starts the delivery of gasolene as will be more fully described hereinafter.

'Ihe pump body is internally threaded at 50 near the upper end 'of its central bore. into which is screwed a hollow stud 5|V fastened to the inner race of ball bearing 52. the outer racc thereof being mounted in the stop plate 42. The inner surface of the top part 53 of stud 5| is longitudinally fluted and engaged hy similar flutes at 54 on stub shaft 55 which is rotatably mounted in the ball bearin 56 carried by the cap potion 2. Upon turnin the handle 51 fixed on theshaft 55. the stud 5 is turned and thus vraised or lowered in the threads at 5|! along the .,iitedvend of shaft 55. -'Tne stop plate 42 is thusraised or lowered but is held from turning byth'e'pressure of the springs 40.

the modification of Fig. 3. the stop plate 58iisan integral part of the hollow stud 59. so

that the stop plate turns. while being raised or vlowered between the full line and broken line 'positions shown, whenever the fiuted shaft 6D Fiss. land 2. 'rms pump 0f Figs- 3 and 4 is P" 69 being substantially identical with the corresponding parts of Figs.. 1 and 2. The' plunger and piston are reciprocal in the barrel of the pump housing 10, which has an inlet .1|, outlet 12, ring inlet port 13 and a delivery port 14 for a delivery conduit (not shown) communicating directly with a nozzle in lthe engine cylinder. The top of the housing 10 is threaded for engagement with a cap 15 having a depression into which the piston spring 69 extends. may be screwed up and down and thereby forms an adjustable stop for the control piston 61. The cap may be releasably held in any adjusted position by the spring ring 16 and ball 11. On opposite sides of the pump housing 10, near the bottom thereof, are two end caps 18 and 19" clamped thereagainst by the screws 80. The end plate 18 carries a ball bearing 8| and the end plate 19 carries a ball bearing 82 and an oil seal 83.

In Fig. 6 is shown a modified formof plunger piston springs which may be applied to each of the single or multicylinder -pumps of the previous l Figs. 1 and 2 will now be described. The pump shaft 43 is driven at cam shaft speed fora 4- cycle engine, or at crank shaft speed for a 2- cycle engine, in proper timed relation thereto. and the swash plate 49 then raises the delivery plungers 35 in tum progressively. During operation of the pump, gasolene flows into the inlet I0 and iills the circular channels I8. |9 and the interiors of all delivery plungers and control pistons open at the time to the channels through the inlet ports 20. The surplus supply of gasolene flows around the outside of the screen 5 and continuously washes away any particles of dust, dirt or other foreign matter there deposited. As each delivery'plunger rises and closes its inlet port 20. pressure on the substantially incompressible gasolene is quickly built up to overcome -control piston 31, the entrapped gasolene is subjected to ever increasing pressure as the lift of the delivery plunger continues, until the pressure on the gasolene in the duct 30 at the nozzle 3| reaches that required to lift the springpressed pin of the nozzle to open the spray passages into the engine manifold 32. The delivery of. gasolene spray into the manifold then continues until the delivery plunger is at the end of its upward stroke (as shown at the right in Fig. I). Any gasolene leaking past the delivery plunger to the channel 22 iiows'lnto the trap I8 from whence it, with the surplus gasolene from inlet I0, flows to the pump outlet Il. Thence upon the downward suction stroke of the delivery plunger, caused by the spring 39 as permitted by the swash plate H9, the control piston 31 follows under action of its spring 40 to its bottom limit (substantially as indicated at the left of Fig. 1), a fresh supply of gasolene being taken in tothe interior' of the barrel while the inlet channel 20 is again open. The point in the engine cycle at which the injection begins, and the quantity of gasolene delivered, are thus predetermined by the position of the stop plate 42 as adjusted by the handle 51. Likewise with the modified form of adjustment shown in Fig. 3, this point is predetermined by the stop plate 58 as adjusted by the handle 8|. It is thus apparent that the control piston controls a delivery characteristic of the plunger.

The stop plate I2 of Fig. l and the stop plate 58 of Fig. 3 may be raised or lowered by the manual adjusting handle 51 or 6I as the case may be. In either case, the gasolene is discharged from each pump barrel through the delivery port 2| as soon after the control piston 31 engages the stop plate as the delivery plunger is lifted enough higher to develop that pressure on the gasolene sufficient to open nozzle 3|.

Irrespective of the adjusted position of the stop plate of either form, the pressure on the gasolene delivered from each barrel rises to its delivery pressure in a few degrees o f the pump cycle after the'control piston engages the stop plate. Owing to the sine wave characteristic of the upward lift of the delivery plunger by the swash plate, there is a period of about 30 in the pump. cycle in which there is a substantially constant speed of the delivery plunger. In this period, the time rate displacement of the delivery .plunger is substantially constant and therefore the volume of fuel discharge is at a substantially constant rate. Thereafter, the work piston decelerates in its speed of upwardA movement and the volume rate of the fuel discharge consequently decreases, while the pressure on the fuel similarly decreases until the needle of nozzle 3| is Aclosed by its spring. For the remainder of the upward stroke of the piston. if any, the fuel is discharged past the control piston into the trap channel 22. Owing to the fact that there is no delivery valve controlling the delivery port, and no check valve in the pump or in the conduit leading from it to the nozzle, and furthermore due to the fact that the pressure of the springs 39 and it varies but slightly during the period of lift of the pistons, the pressure on the gasolene in the pump cylinder during substantially the whole period of delivery of fuel is atvsubstantially the minimum possible under the conditions.- This-feature reduces the precision necessary in the fits between pistons and barrels, and reduces the leakage past the control pistons. Furthermore, it reduces the weight of the pump and working parts necessary to withstand the pressure. Concomitantly, this increases the rigidity of the parts against mechanical distortion with the consequent improvements in operation and durability. Not only does the'absence of all delivery valves, check valves, and modifying springs simplify the construction, but the use and arrangement of the circularly disposed tubes 23 further strengthen the pump and result in less weight for the same rigidity and output capacity than would otherwise `be the case.

The operation of the single cylinder pump of Figs. 4 and 5 will now be understood from the foregoing, the difference residing mainly in the gasolene are substantially the same as described above. In this case, it is the pressure of -the gas'olene alone, and not that in addition to the pressure of the spring on the delivery plunger, that lifts the control piston to its stop plate.

The hollow delivery plungers of the single and multicylinder pumps herein are expansible from a comparatively loose fit to a tight flt in the barrel as pressure is developed in the gasolene. Also the filter cage may be readily exposedand removed for inspection and replacement upon removing the filter housing. Furthermore, the

' clearing of the screen is aided by thev pumps in forcing back through it some of each charge of gasolene'A initially sucked into the barrels on the downward stroke of the plungers, which, together with the proximity to the screen of the inlet Lli) (lll

ports, ensures the supply of clean gasolene to all the barrels throughout extended periods of use. Having thus described my invention, what I claim is:

1-. In a liquid pump having a. plunger barrel with inlet and outlet ports, a hollow delivery plunger reciprocative in said barrel, operating means acting to move said plunger in its delivery stroke to force liquid through said outlet port. a spring extending into the plunger and acting to effect its return suction stroke and draw liquid through said inlet port into said barrel, and a control piston in said barrel for controlling the amount of liquid delivered through the outlet portin each delivery stroke of said plunger.

2. In a liquid pump having a barrel with inlet and outlet ports, a hollow delivery plunger and' a hollow control piston reciprocative in said barrel. said piston controlling the amount of liquid delivered through the outlet port in each delivery stroke of said plunger, operating means acting to movesaid plunger and piston in their delivery strokes to force liquid through said outlet port, a spring extending into said plunger and acting to effect its return suction. stroke and draw liquid through said inlet port into said barrel, and a spring extending into said piston and acting to effect its return stroke. f

3. In a liquid pump having a barrel with inlet and outlet ports, a hollow delivery plunger and a hollow control pistonreciprocatlve in said barrel, operating means acting to move said plunger and piston in their delivery strokes to force liquid through said outlet port, a spring extending into said plunger and acting to effect its return suction stroke and draw liquid through said inlet port into said barrel, a stop member cooperative with said piston to control the amount'of liquid delivered through the outlet port in each delivery stroke of said plunger, and a spring extending into said piston and reacting' between it and the stop member and acting .t0 effect the return stroke of said piston.

4. In a liquid' pump having a barrel with inlet and outlet ports, a hollow delivery plunger and a hollow control piston reciprocative in said barrel, operating means acting to move said plunger and piston in their delivery strokes to force liquid through said outlet port, a spring extending into said plungerand piston and reacting therebetween, a stop member cooperative with said pis.-v tonto control the amount of liquid delivered through the outlet port in each ldelivery stroke of the plunger, and a spring extending into said piston and reacting between it and said stop member, said springs actingto effect the return suction strokes of said plunger and piston and draw liquid through said, inlet port into said barrel.

. 5. In a liquid pump having a barrel with inlet *and outlet ports, a hollow delivery plungerand a hollow control piston reciprocative in said barrel, operating means acting to move said plunger and piston in their delivery strokes to forceliquid through said outlet port, a spring extending into said plunger and reacting against said barrel for moving said plunger in its return suction stroke to draw liquid through said inlet port into said barrel, a stop membergcooperative with said piston to control the amount of liquid delivered through the outlet port in each delivery stroke of said plunger, and a spring extending into said piston and reacting between it and said stop member.

6. In' a liquid pump having a plunger barrel with inlet; and outlet ports, a hollow delivery plunger reciprocative in said barrel, operating means acting to move said plunger in its delivery rocative delivery plungers and control pistons in said barrels, operating mechanism for reciprocating, said plungers and pistons, an adjustable' stop mechanism arranged near one end of -said bore and having an adjustable stop plate for'said with a delivery port, delivery plungers in said stroke to force liquid through said outlet port,

a sp1- ing extending into said plunger and acting to effect its return suction stroke Iand drawliquid through said inlet port into said barrel, and control means including a piston movable in said .barrel for controlling the amount of` liquid delivered through the outlet port in each delivery stroke of said plunger, said barrel having a trap which throughout the movement of said piston in said barrel is in registry with lsaid piston and in communication with said inlet port.

7. In a liquid pump, a reciprocative delivery plunger, a reciprocative control piston for said plunger, an adjustable stop member for said piston, operating means for reciprocating the plunger and piston, and rotatable and axiallymovable adjustable mechanism including a nonrotatable member arranged to engage the piston to limit its reciprocative movement in one direction.

8. In a multicylinder liquid pump, an integral barrels, operating means for reciprocating said plungers, for each barrel a tubular member in communication with said delivery port to form a delivery conduit therefor, and a casing enclosing said body and assisting in holding said tubular members in place therein. y

12. In a multicylinder liquid pump, a pump b'ody having a plurality of circularly-disposed plunger barrels each with a delivery port, delivery plungers in said barrels, operating means for reciprocating said plungers, arranged radially of each barrel a tubular member in communication with said delivery port to form a delivery conduit therefor, and a'casingenclosing said body and `assisting in holding said tubular members in placetherein.

13. In a multicylinder liquid pump, a pump bodyhaving a plurality of plunger barrels each with a delivery port and having integral flanges,

delivery plungers in said barrels, operating means for reciprocating said plungers, for each barrel a tubular member passing through said flanges and arranged in communication with the delivery port of its barrel to form a delivery conduit reciprocative in said barrel to deliver liquid from pump body having a plurality of delivery barrels and a threaded portion, reciprocative delivery plungers and control pistons in said barrels, operatingl means for reciprocating said plungers -and'pistons and an adjustable stop mechanism arranged in engagement with said threaded portion and having an adjustable stop. for said pistons.-

9. In a multicylinder liquid pump, an integral pump body having a. plurality of circularlydis pos'eddelivery barrels and a central threaded bore, reciprocative delivery plungers and controlA pistons in said barrels', operating means for rel ciprocating said plungers and pistons, an adjustable stop mechanism comprising a ,rotatable member in engagement with said threaded portion and a stop plate for said pistons supported' on a bearing in said rotatable member, and springs reacting between said pistons and stop v plate.

1o. 1n a mumeyunder uquid pump,anintegra1 pump body having a plurality of circularly-dis- 75 therefor, and a casing enclosing said body and assisting in holding said tubular members in` place.

14. -In a liquid pump having a plunger barrel with inlet and outlet ports, a delivery plunger said inlet port to said outlet port, a casing surrounding `said barrel and having inlet and outlet ports in communication with each other and with the inlet port of said barrel, and a stationary filter in said casing interposed between the inletports of said casing and barrel, said pump having means for returning surplus liquid from said barrel through said filter to assist in cleansing the same.

15. In aV multicylinder liquid pump having plunger barrels with inlet and outlet ports, delivery plungers operative in said barrels to deliver liquid from respective inlet ports to respective outlet ports,l a casing surrounding said barrels and having inlet and outlet ports in communication with each other and with said inlet ports of the barrels, and a stationary filter in said casing interposed between said inlet ports of said casing and barrels, said pump having means for returning surplus liquid from said barrels through said filter to assist in cleansing the same.

V16. In a multicylinder liquid pump having plunger barrels with inlet and outlet ports, delivery plungers operative'in said barrels to deliver liquid from respective inlet ports to respective outlet ports, a perforated filter cage surrounding said barrels, a stationary filter covering the perforations of said cage, and acasing surrounding said cage and having inlet and outlet'ports in communication with each l other around the outside of said filter, said pump having means for returning surplus liquid from said barrels through said filter to assist in cleansing the same.

ing the same.

l1.' In a multicyli'nder liquid pump, a pump housing having a plurality of circularly-arranged plunger barrels with inlet and outlet ports, delivery plungers operating in said barrels to deliver liquid from respective inlet ports to respective outlet ports, a casing surrounding said pump body and having inlet and outlet ports in communication with each other, and a stationary y circular filter fastened around said pump hous ing and held in place by said casing, said pump vhaving means for returning surplus .liquid from said barrelsthrough saidlter to assist in cleans- 18. In a niulticylinder liquid pump, a pump body with a plurality of vcircularly-arranged plunger barrels with inlet ond outlet ports, delivery plungers operative in said barrels 'to deliver liquid from respective inlet ports to respective outlet ports, a plurality of circularly-disposedtubular members in communication with respective outlet ports of said barrels, a stationary circular illter surrounding said tubular members,

and a casing surrounding said filter and havingA inlet and outlet ports in communication with each other around said filter, said tubular menibers and said lter being held in place by said casing, and said pump having means for returnthrough said outlet port, and control means including va piston in said barrel for controlling the amount of liquid delivered through the' outlet port in each delivery stroke of said plunger.

20. In a liquid pump having a plunger barrel with an inlet port and an outlet port throughl its wall, a hollow plunger reciprocative vin said barrel, reciprocating means acting to move said plunger in its suction stroke to draw liquid through said inlet port into said barrel and-to move said plunger in its delivery stroke to 'force liquid from said Abarrel through said `outlet port,- 4and control means including a piston in said barrel'for controlling the amount of liquid delivered through the outlet portl in each delivery stroke of said plunger.

BEN G. PARSONS. 

